Would it not be good to add Sittuyin and Makruk to the chess variants?

 Makruk is a Thai regional sort of chess. It is quite similar to the Western chess game, but has some slight differences in how the pieces move and in some other miscellanious rules.
 Sittuyin is a Burmese variation of Makruk, it has a very interesting feature of allowing the players to adjust the starting position of their pieces to their liking (with some rules, of course), which adds some strategy at the very beginning of the game.
You can find the exact rulesfor both games on the internet, if you're interested.

 Provided that both of these chess games are currently suffering from being displaced by Western Chess in their respective regions and have little to no digital platfroms to be played online on, I think that chess.com would not merely add some new "game modes", but also commit to the preservative and popularisation efforts, which, I reckon, is a cause good enough.

I am not sure of how responsive the administration is to such pleas, but I think that with enough popular support we could achieve the inclusion of these and maybe some other endangered chess variants to the site.
What do you think?

I do sympathize with your idea. I am suspicious as I like regional chess variants a lot. See this following website if you haven't. Not only has FIDE chess variants but I think the main regional ones (https://www.pychess.org/). Cheers

I second Rincov's suggestion. PyChess is a wonderful open-source website where you can play Makruk against other players or computer opponents.

Besides Thai chess, it also has Cambodian chess (Ouk Chatrang), Burmese chess (Situyin) and a variant of Makruk called Makpong. Unfortunately, the site still isn't very popular, so sometimes it takes patience until someone takes your seek.

It's really worth a try.

https://www.pychess.org/